Decoding the spatiotemporal organization of the chromosome in a predatory bacterium

This thesis delves into the unique cellular processes of Bdellovibrio bacteriovorus, a predatory bacterium that preys upon Gram-negative bacteria. Featuring two lifecycle phases, the attack phase, and the growth phase, Bdellovibrio employs a non-binary mode of division. I report that during the AP, the nucleoid is centrally positioned and polarized. In the GP, multiple and asynchronous rounds of DNA replication occur. The chromosome segregation is progressive, decoupling the partitioning of the ter regions from final cell constriction. I also examined the ParABS system, which is essential for chromosome segregation. Unlike in binary-dividing bacteria, it is adapted for separating multiple DNA copies and has complex regulation. I have also identified four additional ParA-like proteins, hinting at novel functions. Overall, my work enriches our understanding of Bdellovibrio’s biology and opens new avenues for research in bacterial physiology and cellular organization.